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A water quality variance is a temporary change in a state's water quality standard for a specific pollutant and its relevant criteria, allowing deviation from meeting a water quality-based effluent limit for a particular discharger.

Standard operating procedures (SOPs) reflect how agency staff and contracted partners complete agency-funded field activities.

Excess nitrate remains a long-term challenge to manage. In our lakes, rivers, and streams, it is toxic to fish and other aquatic life. In drinking water, it can pose a risk to human health,…

The Clean Water Act established the framework for creating water quality standards and continues to help us protect Minnesota's prized lakes and rivers.

Across the state, water softeners contribute significantly to chloride pollution. Here’s how to make sure your water softener isn’t sending excess salt into the environment

Water scientists from the MPCA published four watershed reports in 2025, updating the data we need to keep Minnesota’s waters clean and protected.

The MPCA monitors and assesses lakes around the state to determine if they meet water quality standards.

This committee included a broad range of stakeholders and was charged with providing perspective, input, and advice to the commissioner on MPCA's water fees.

Planned amendments to Minn. Rules ch. 7050 affect the Class 1 beneficial use, which protects waters (both surface and groundwater) used as a source for domestic consumption.

Dakota County is now hosting We Are Water MN, a traveling exhibit and community engagement program that explores Minnesotans’ relationships with water.

The MPCA proposes to adopt the U.S. EPA's 2013 national recommended water quality criteria for ammonia as its Class 2 ammonia water quality standards for the protection of aquatic life.

Southeastern Minnesota is characterized by an unusual type of geography called karst, where the distinction between groundwater and surface water is blurry.

The MPCA plans to amend Minnesota Rules chapter 7050, which establishes beneficial uses and water quality standards to protect those uses, and designates where the uses occur in waters of the state.

A watershed is the area of land where all of the water that drains off of it goes into the same place — a river, stream or lake.

Wild rice is an important part of the biological community in many Minnesota lakes, streams, and wetlands, and a cultural resource to many, particularly members of the Dakota and Ojibwe Tribal Nations in Minnesota.

Water quality trades that have been arranged in Minnesota illustrate many opportunities to enhance pollution reduction efforts while offering flexibility and cost savings to regulated municipalities and industries.

The MPCA uses the Environmental Quality Information System (EQuIS) to store water quality data from more than 17,000 Minnesota sampling locations.

Waterways in the northeastern part of the state are generally in better condition than those in the southern, central, and western regions.

Online tool showing Minnesota waters failing to meet one or more water quality standards.

Chloride is a problem for wastewater facilities and stormwater permittees.